In the prior art there are many types of structural masts, poles requiring the assembling on a level ground and then tilted into vertical position by lifting the top end of the mast by crane. Such type of masts and poles assembly requires a very long clear working area that is substantially horizontal and free of any obstacles such as constructions, trees and vegetation.
Such commonly known in the art construction technology is expensive and not efficient.
Another method and device to lift a pole is described in U.S. Pat. No. 5,794,387 generally includes the pole and bases, lower frame which extends along the ground. Lower frame comprises elongated beams and cross beams. Also, the device includes the collar connected to the left ends of beams, two elongated side rails that are positioned to straddle opposite sides of pole and base, cross braces holding the rails in spaced apart parallel position but are U-shaped to allow pole to be centered between rails, the auxiliary tower pivotably attached by pivots to lower frame, the hydraulic cylinders (jacks) facilitating the tilting action of the auxiliary tower with the inserted pole, and more components providing the griping and lifting operation for pole erection.
This device is complex and does not provide the erection of the massive, high (over 30-100 feet) poles, columns and/or masts.
Some types of structural masts can be erected in more convenient method: to transport the tower by sections or partial sections by means of helicopters into a cleared area only sufficiently large to assemble the mast in a vertical position. This method to rise the masts (e.g. TV-masts), poles, columns and piers requires the use of cranes with the boom that is longer than the total height of the mast.
The use of the crane increases the construction expenses and requires more space under construction.
The process of erecting vertical rising mast disclosed in U.S. Pat. No. 3,945,107 describes a system which is intended for section by section assembling in a vertical position, as distinguished from the conventional method of raising a mast by assembling the mast in a horizontal position on the ground and then lifting the mast into a vertical position. The mast is made of a base section and a plurality of upper sections, each one adapted to be mounted on top of the one below it and fastened thereto. After the base section has been assembled on the foundation, the succeeding sections are assembled on the ground or are lifted in pieces and assembled in place on top of the previous section by means of a floating gin pole. The gin pole is supported inside of the mast by means of a plurality of basket cables, which are attached at one end to the bottom of the gin pole and attached at their other ends to a corresponding plurality of points on the top of the last previously positioned section. The floating gin pole extends above the top of the topmost assembled section, and can tilt to the outside of the mast, so as to lift section parts outside the mast. When the bottom end of the gin pole is supported in this way, luffing lines can be attached to the top end of the gin pole, and attached to small winches which are fastened to the top of the last previously positioned section, as the mast is being erected. Since the gin pole extends well above previously assembled section, it extends far enough to the side of the mast to pick up parts of the upper sections, which can be lifted into position on top of the previously assembled section and fastened to it. As each section is added to the mast, the gin pole is lifted by one section, the basket lines being fastened to corresponding points on the section above.
Also the system includes a plurality of jump lines which are attached to the newly added section near its top, by means of which the base end of the floating gin pole can be lifted so that the basket lines can be moved to their corresponding positions on the newly added section. Then, after another new section is added, the base of the floating gin pole is again lifted and the basket lines moved up another section and so on. In this manner each of the sections in turn can be added to those already in place, until the mast is completely assembled. The remaining step is to remove the floating gin pole from the structure. The means for removing the gin pole is positioned on the top of the mast an auxiliary support and block means. This can be a conventional jib boom, by means of which the lifting cable and winch can be used to lift the gin pole, so that the basket cables can be removed and the gin pole can then be lowered to the ground down through the inside of the mast. The jib boom is then used to assemble the crown assembly and the crown block on top of the top section of the mast. After the top of the mast is completed a jib boom, or auxiliary support and block means, is mounted on the top section and used as a means to lower the floating gin pole to the ground. The auxiliary support means is then used to assemble the crown block on top of the mast. The jib boom is mounted on the top section and used as a means to lower the floating gin pole to the ground. The auxiliary support means is then used to assemble the crown block on top of the mast.
Such device is complex, requires basket cable system for built-in crane-like equipment.
Thus, there is a great need in the art for the improved self-lifting vertically rising mast, providing convenient, economical, effective and safe construction process and device for high masts, poles and columns erection.